# CVE-2026-65704: FFmpeg 8.1.2 Out-of-Bounds Write via TY Demuxer and Shorten Decoder

> Attackers can achieve code execution or denial of service via heap corruption in FFmpeg when processing crafted files with the -safe 0 flag.

- **Severity:** High 7.3 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 23 Jul 2026
- **Updated:** 28 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-65704, ECHO-7d2e-9fad-304d, GHSA-98cx-cw6c-5pj4, JLSEC-2026-1179, MINI-fg4x-jh6j-c22h, UBUNTU-CVE-2026-65704

## What is CVE-2026-65704?

CVE-2026-65704 is a high-severity memory corruption vulnerability in Ffmpeg Ffmpeg, published on 23 Jul 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

FFmpeg through 8.1.2 contains an out-of-bounds write vulnerability that allows attackers to cause heap corruption by supplying a crafted ffconcat file processed with the -safe 0 flag. The TY demuxer's demux_audio() function decrements packet size without bounds checking, producing a negative size value that is passed to memcpy() in shorten_decode_frame(), where conversion to size_t wraps the value to near SIZE_MAX and triggers reads beyond the source allocation and writes far beyond the Shorten decoder's bitstream buffer.

Weakness: CWE-787 (Out-of-bounds Write), CWE-191 (Integer Underflow (Wrap or Wraparound))

## Which versions are affected by CVE-2026-65704?

It affects 1 product.


Products: Ffmpeg Ffmpeg.

## How do I fix CVE-2026-65704?

Apply the vendor's patch.

## Is CVE-2026-65704 being exploited?

There is no known exploitation of CVE-2026-65704 in the wild and no public exploit code.

## Other vulnerabilities in Ffmpeg Ffmpeg

- [CVE-2013-0864](https://insights.sbomify.com/CVE-2013-0864/): Memory corruption in n/a (critical 10.0)
- [CVE-2013-0872](https://insights.sbomify.com/CVE-2013-0872/): Memory corruption in n/a (critical 10.0)
- [CVE-2013-0873](https://insights.sbomify.com/CVE-2013-0873/): Memory corruption in n/a (critical 10.0)
- [CVE-2013-4265](https://insights.sbomify.com/CVE-2013-4265/): Null dereference in n/a (critical 10.0)
- [CVE-2011-3937](https://insights.sbomify.com/CVE-2011-3937/): Memory corruption in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-65704 and fix it if it is affected.

What it is: CVE-2026-65704 is a high-severity memory corruption vulnerability in Ffmpeg Ffmpeg, published on 23 Jul 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-65704 in the wild and no public exploit code.

Affected product: Ffmpeg Ffmpeg. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-65704/ (Markdown: https://insights.sbomify.com/CVE-2026-65704/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-65704
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-65704
- OSV: https://osv.dev/vulnerability/CVE-2026-65704

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-65704/
Summaries are generated and may contain mistakes; the official description above is the record.